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libc, libthr: use AT_USRSTACK{BASE,LIM} instead of sysctl("kern.usrstack") and get_rlimit(RLIMIT_STACK)

Browse Source 
Reviewed by:	brooks, imp (previous version)
Discussed with:	markj
Sponsored by:	The FreeBSD Foundation
MFC after:	2 weeks
Differential revision:	https://reviews.freebsd.org/D36540
This commit is contained in:
Konstantin Belousov 2022-09-12 22:45:21 +03:00
parent ebf7a01594
commit e2879ece43
3 changed files with 49 additions and 29 deletions
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27
lib/libc/gen/elf_utils.c
View File

@ -29,6 +29,7 @@
*/
#include <sys/param.h>
#include <sys/auxv.h>
#include <sys/mman.h>
#include <sys/resource.h>
#include <sys/sysctl.h>
@ -77,19 +78,23 @@ __libc_map_stacks_exec(void)
{
int mib[2];
struct rlimit rlim;
u_long usrstack;
u_long usrstack, stacksz;
size_t len;
mib[0] = CTL_KERN;
mib[1] = KERN_USRSTACK;
len = sizeof(usrstack);
if (sysctl(mib, nitems(mib), &usrstack, &len, NULL, 0)
== -1)
return;
if (getrlimit(RLIMIT_STACK, &rlim) == -1)
return;
mprotect((void *)(uintptr_t)(usrstack - rlim.rlim_cur),
rlim.rlim_cur, _rtld_get_stack_prot());
if (_elf_aux_info(AT_USRSTACKBASE, &usrstack, sizeof(usrstack)) != 0) {
mib[0] = CTL_KERN;
mib[1] = KERN_USRSTACK;
len = sizeof(usrstack);
if (sysctl(mib, nitems(mib), &usrstack, &len, NULL, 0) == -1)
return;
}
if (_elf_aux_info(AT_USRSTACKLIM, &stacksz, sizeof(stacksz)) != 0) {
if (getrlimit(RLIMIT_STACK, &rlim) == -1)
return;
stacksz = rlim.rlim_cur;
}
mprotect((void *)(uintptr_t)(usrstack - stacksz), stacksz,
_rtld_get_stack_prot());
}
#pragma weak __pthread_map_stacks_exec

25
lib/libthr/thread/thr_init.c
View File

@ -38,6 +38,7 @@ __FBSDID("$FreeBSD$");
#include "namespace.h"
#include <sys/param.h>
#include <sys/auxv.h>
#include <sys/signalvar.h>
#include <sys/ioctl.h>
#include <sys/link_elf.h>
@ -462,18 +463,26 @@ init_private(void)
if (init_once == 0) {
__thr_pshared_init();
__thr_malloc_init();
/* Find the stack top */
mib[0] = CTL_KERN;
mib[1] = KERN_USRSTACK;
len = sizeof (_usrstack);
if (sysctl(mib, nitems(mib), &_usrstack, &len, NULL, 0) == -1)
PANIC("Cannot get kern.usrstack from sysctl");
if (elf_aux_info(AT_USRSTACKBASE, &_usrstack,
sizeof(_usrstack)) != 0) {
mib[0] = CTL_KERN;
mib[1] = KERN_USRSTACK;
len = sizeof (_usrstack);
if (sysctl(mib, nitems(mib), &_usrstack, &len,
NULL, 0) == -1)
PANIC("Cannot get kern.usrstack from sysctl");
}
env_bigstack = getenv("LIBPTHREAD_BIGSTACK_MAIN");
env_splitstack = getenv("LIBPTHREAD_SPLITSTACK_MAIN");
if (env_bigstack != NULL || env_splitstack == NULL) {
if (getrlimit(RLIMIT_STACK, &rlim) == -1)
PANIC("Cannot get stack rlimit");
_thr_stack_initial = rlim.rlim_cur;
if (elf_aux_info(AT_USRSTACKLIM, &_thr_stack_initial,
sizeof(_thr_stack_initial)) != 0) {
if (getrlimit(RLIMIT_STACK, &rlim) == -1)
PANIC("Cannot get stack rlimit");
_thr_stack_initial = rlim.rlim_cur;
}
}
_thr_is_smp = sysconf(_SC_NPROCESSORS_CONF);
if (_thr_is_smp == -1)

26
lib/libthr/thread/thr_stack.c
View File

@ -31,6 +31,7 @@
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/auxv.h>
#include <sys/mman.h>
#include <sys/queue.h>
#include <sys/resource.h>
@ -149,18 +150,23 @@ singlethread_map_stacks_exec(void)
{
int mib[2];
struct rlimit rlim;
u_long usrstack;
u_long usrstack, stacksz;
size_t len;
mib[0] = CTL_KERN;
mib[1] = KERN_USRSTACK;
len = sizeof(usrstack);
if (sysctl(mib, nitems(mib), &usrstack, &len, NULL, 0) == -1)
return;
if (getrlimit(RLIMIT_STACK, &rlim) == -1)
return;
mprotect((void *)(uintptr_t)(usrstack - rlim.rlim_cur),
rlim.rlim_cur, _rtld_get_stack_prot());
if (elf_aux_info(AT_USRSTACKBASE, &usrstack, sizeof(usrstack)) != 0) {
mib[0] = CTL_KERN;
mib[1] = KERN_USRSTACK;
len = sizeof(usrstack);
if (sysctl(mib, nitems(mib), &usrstack, &len, NULL, 0) == -1)
return;
}
if (elf_aux_info(AT_USRSTACKLIM, &stacksz, sizeof(stacksz)) != 0) {
if (getrlimit(RLIMIT_STACK, &rlim) == -1)
return;
stacksz = rlim.rlim_cur;
}
mprotect((void *)(uintptr_t)(usrstack - stacksz), stacksz,
_rtld_get_stack_prot());
}
void